Heated asphalt storage unit

ABSTRACT

A unit for storing and maintaining asphalt at an elevated temperature as is necessary to facilitate making road repairs with this material, even in cold weather. Instead of applying heat insulation to the walls defining the asphalt storage compartment in an attempt to minimize heat loss therethrough, the storage compartment is enveloped within a body of heated air flowing at a controlled rate and the outer wall bounding the passage for this convection flowing heated air is insulated against heat loss. Thus, what would be an impractical insulated wall construction, both from the standpoint of the thickness and cost, in order to effectively minimize heat loss from a stationary heated body, such as the stored asphalt, is rendered well within practical requirements when it is applied and used for the continuously moving body of heated air. The enveloping heated air results in an optimum heat gradient about the heated asphalt and thus minimizes heat loss therefrom.

United States Patent [72] Inventor Anton H. Heller Levittown, N.Y. [21] AppLNo. 844,090 [22] Filed July23, 1969 [45] Patented Mayll, 1971 [7 3] Assignee Poweray Infrared Corporation Farmingdale, N.Y.

[54] HEATED ASPHALT STORAGE UNIT 4Claims,4Drawing Figs.

[52] U.S.CI ..126/343.5A [51] Int.Cl E0lc 19/45 v[50] FieldofSearch 126/3435, 343.5 (A) [56] References Cited UNITED STATES PATENTS 1,855,961 4/1932 I-largrave 126/343.5A 2,041,359 5/1936 Littleford,Jr. 126/343.5A 2,728,336 12/1955 Elgeti 126/343.5A 3,039,452 6/1962 Lariscy 126/343.5AX 3,386,435 6/1968 Heller 126/343.5A

Primary Examiner-Charles J. Myhre Attorney-Jerome Bauer ABSTRACT: A unit for storing and maintaining asphalt at an elevated temperature as is necessary to facilitate making road repairs with this material, even in cold weather. Instead of applying heat insulation to the walls defining the asphalt storage compartment in an attempt to minimize heat loss therethrough, the storage compartment is enveloped within a body of heated air flowing at a controlled rate and the outer wall bounding the passage for this convection flowing heated air is insulated against heat loss. Thus, what would be an impractical insulated wall construction, both from the standpoint of the thickness and cost, in order to effectively minimize heat loss from a stationary heated body, such as the stored asphalt, is rendered well within practical requirements when it is applied and used for the continuously moving body of heated air The enveloping heated air results in an optimum heat gradient about the heated asphalt and thus minimizes heat loss therefrom.

I INVENTOR ANTON H. HELLER ATTORNEY PATENTEUMAYmsn 5 v I SHEUEUFZ IN VENTOR ANTON H. HELLER ywm ATTORNEY HEATED ASPHALT STORAGE UNIT The present invention relates generally to techniques for handling asphalt preparatory to making road repairs, and more particularly to an improved unit for storing asphalt at an elevated temperature as is required to maintain the flowability and other characteristics of this material which contribute to its facilitated use for making road repairs.

Presently known asphalt storage units, both of the portable and stationary type, utilize burners and other such heat sources to supplement any heat loss from the asphalt which is being used for road repair. Since the temperature of asphalt which is being used for road repairs should be at or near a temperature of approximately 275 F., during the winter months it is almost impossible to successfully make road repairs since there is at this time significant heat loss from the asphalt which cannot be easily supplemented by the heat source. This, of course, is due to the fact that the heat loss from the asphalt naturally increases as a function of the disparity between the temperature of the ambient weather and the noted optimum temperature of 275 F.

One solution for maintaining the asphalt at its elevated temperature, although not a very practical nor successful solution, is to insulate the walls bounding or defining the asphalt storage compartment against heat loss and, in this way, attempt to minimize heat loss from the asphalt. To be effective, however, the thickness of the heat insulation which is required is of such an extent, and its construction and attachment to the supporting walls so complicated, that this solution is not practical. Another technique, which has been utilized by the present applicant, is to maintain a freely flowing current of heated air about the asphalt storage compartment, relying almost entirely on the temperature gradient which is thus created to minimize heat loss from the asphalt.

The inventive contribution of the present application is a noteworthy extension of applicants aforesaid technique of using an enveloping body of heated air about the asphalt storage compartment. That is, it contemplates the creation of the noted optimum heat gradient which minimizes heat loss, and also the use of heat insulation, The latter is at a practical, advantageous location and of a size to substantially increase the effectiveness of the enveloping heated air. Thus, an underlying contribution of the present invention is the recognition that while heat insulation cannot effectively be used when directly applied to the asphalt storage compartment walls for the reasons already indicated that a practical amount thereof in a practical installation can be used along the outer wall which bounds the flow passageways for the heated air. By minimizing heat loss from the heated air, this air can better perform its function of providing the necessary slight heat gradient in an enveloping position about the heated stored asphalt so that there is a corresponding slight and nominal tendency for there to be any heat loss from the asphalt. Stated another way, applicant has recognized that a moving body of heated air can be insulated against significant heat loss by virtue of its movement and the continual replenishment of any heat loss therefrom by a burner or other heat source of practical size, whereas a stationary heated body, such as the heated asphalt stored within the unit, cannot be significantly insulated by conventional and known insulation means against significant heat loss.

Additionally, the improved storage unit hereof derives more efficiency from the heated air by controlling the flow rate thereof, rather than permitting unrestricted exhausting of this heated air to atmosphere.

A heated asphalt storage unit demonstrating objects and advantages of the present invention includes an outer wall construction bounding a comparatively large internal volume having an inner wall construction positioned within the internal volume and in a clearance position from the outer wall construction such that there is an airflow passageway defined between these two wall constructions. During positioning of the two wall constructions, a heating chamber is delineated and burners are located in this heating chamber to apply heat to the air therein. The heated air expands from this heating chamber through the flow passageways between the wall constructions and thereby envelopes the storage compartment. Moreover, the restricted outlet of the heated air provides a controlled, slow rate of flow in which the heated air is replenished as a function of its heat loss rather than being con tinuously replaced as occurs in an open, free flowing system. Additionally, as already noted, the outer wall construction bounding the flow passageways has heat insulation applied to it so that there is little or no heat loss from the enveloping air through the outer wall construction. As a consequence, an optimum heat gradient is maintained about the heated stored asphalt which minimizes heat loss from the asphalt.

The above brief description, as well as further objects, features and advantages of the present invention, will be more fully appreciated by reference to the following detailed description of a presently preferred, but nonetheless illustrative embodiment in accordance with the present invention, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a storage unit according to the present invention in which positions of movement of doors thereon are illustrated in full line and phantom line perspective;

FIG. 2 is a side elevational view, in section taken along line 2-2 of FIG. 1, illustrating internal structural features thereof;

FIG. 3 is a plan view, in section taken along line 3-3 of FIG. 2, illustrating additional internal structural features thereof; and

FIG. 4 is an end elevational view, in section taken along line 4-4 of FIG. 2, illustrating the internal structural features thereof from another perspective.

Reference is now made to the drawings wherein there is illustrated a storage unit, generally designated 10, which is intended for use in storing heated materials. One such material is asphalt as is used in making road repairs. Although not shown, it will be understood that unit 10 may be mounted on a vehicle or it may be provided with wheels, so that in either case it is rendered portable. The asphalt which is to be stored within the unit 10 as already noted, is required to be at an elevated temperature which facilitates, in an obvious and known manner, the making of road repairs. Thus, the unit 10 must be capable of storing this heated asphalt for sufficiently long periods of time without an appreciable loss of heat therefrom as would lower the asphalt temperature to a point at which this material cannot be conveniently used to make road repairs. This is achieved in the unit 10 in a novel way. Rather than attempt to directly heat the asphalt and, in this way, supplement any heat loss therefrom, the mode of operation of the unit 10 contemplates insulating the storage chamber of the asphalt so that there is no significant loss of heat in the first instance. Moreover, it is recognized that the form of insulation necessary to achieve this result, if embodied in a conventional wall construction using conventional materials would be prohibitive both in cost and in complexity of construction. Accordingly, novel use is made in the unit 10 of a continuously controlled flow or current of heated air about the asphalt storage unit which is maintained at a temperature whichis approximately that of the temperature of the heated asphalt. As is well known, heat transfer requires a temperature gradient and since the enveloping air about the storage compartment is at the same temperature as the materials stored therein, the temperature gradient necessary for heat transfer is lacking and thus there is an optimum, minimum amount of heat loss from the stored materials. Furthermore, it has been found that the heating units required to heat the flowing air are well within what can practically be provided in the storage unit 10. Also, it is feasible to embody heat insulation in a wall construction that can effectively minimize heat transfer from a continuously flowing body of heated air, whereas an insulated wall construction, as already noted, would not be feasible to prevent any appreciable heat loss from the stationary heat asphalt material.

Turning now more specifically to the construction of the unit 10, the same has an outer wall construction including opposing end walls 12 and 14, sidewalls l6 and 18, a bottom wall 20, and finally, a pair of pivotally mounted doors 22 and 24, all of which cooperate with each other to bound or define a comparative large first internal volume 26.

Operatively arranged within the first volume 26 is an open inner wall construction which includes opposite end walls 28 and 30, sidewalls 32 and 34, bottom wall sections 36 and 38 and, finally, a centrally located pair of intersecting walls 40 and 42 which complete the bottom for the inner wall construction. As is readily apparent from the drawings, the inner wall construction which is generally designated 44, bounds or defines a second internal volume 46 which is of a lesser extent than the internal volume 26 of the outer wall construction. As is perhaps best illustrated in FIG. 3, this difierence in size between the inner inner and outer wall constructions enables the positioning of the inner wall construction such that there is clearance space therebetween which defines two air passageways 48 between the outer sidewalls l6 and 18 and the inner sidewalls 32 and 34. Still referring to FIG. 3, it should be further noted that each air passageway 48 communicates at one end with a heating chamber 50 which is defined by the centrally located angularly inclined walls 40 and 42 (see FIG. 2). At an opposite remote end, each passageway 48, as best shown in FIG. 4, communicates through openings 52 and S4 in the walls 32 and 34, respectively, with a heated asphalt storage compartment 56 which is delineated by each half of the inner wall construction on opposite sides of the heating chamber 50. That is, one of the asphalt storage compartments 56 is bounded, as best shown in FIG. 2, by walls 28, 36 and 40, while the other by walls 42, 30 and 38, and both of the compartments 56 are then completed, as best shown in FIG. 3, by the opposite sidewalls 32 and 34 which are an integrated part of the structure which provides the previously noted air passageways 48. The significance of the foregoing will soon be apparent.

As best illustrated in FIGS. 2 and 3, mounted within the heating chamber 50 are infrared burners which function, in a well understood manner as a source of heat which is advantageously transferred by radiation through the walls 40 and 42 to the stored asphalt materials within the storage compartments 56. A more important function of the burners 58, however, is its function as a. heat source for ambient air which enters the heating chamber through vents 60 and 62 in a door 64 leading into the heating chamber 50. This entering air, herein illustrated by the arrows designated 66, as a result of the heating by the burners 58 expands and thus flows out of the heating chamber 50 into each air passageway 48. This flowing air, as best shown in FIG. 4, follows a flow path of complete envelopment around the inner wall construction 44 and eventually passes through the previously noted openings 52 and 54 of the walls 32, 34 and enters into the storage compartments 56. From the storage compartments, the heated air is eventually forced out to atmosphere through the apertures or vents 68 and 70 which are provided in the door 24. This assures a continuous flow of heated air from the burners to the atmosphere and a consequent heating of all of the walls of the storage compartment. The just described controlled or constrained flow of heated air from the heating chamber 50 is a continuous, convection flow and, as will be described subsequently herein, contributes in a significant way to the ability of the storage unit to maintain the stored material at an elevated temperature with minimum heat loss.

For completeness sake, it should be noted that the end walls 28 and 30 of the inner wall construction are each provided with lever-actuated doors 72 and 74 by which the user can readily obtain access to the stored materials within the storage compartments 56. In FIG. 2, door 72 is shown in its raised position uncovering a shoveling opening 76 by which the stored asphalt can be removed by shovel preparatory to making road repairs. An insulated pair of doors 78 and 80 are located adjacent the end walls 14 and I2 zmd cooperate with these walls to define storage areas 82 and 84 for tools or the like and also to provide shoveling decks 86 and 88 which facilitate the shovel removal of the asphalt.

The loading of the storage unit 10 is naturally achieved through the top opening of the unit which is created by opening movement of the doors 22 and 24 through the movement transverse illustrated by the full line and phantom line perspective representations of the doors 22 and 24 in FIG. 1. This door movement is also illustrated in full line and phantom line perspective in FIG. 4. Facilitating this movement is a conventional arrangement of linkages, individually and collectively designated 90, which function, in a well understood manner, to provide a mechanical advantage which overcomes the weight of the doors 22 and 24. Also, the open position of the doors 22 and 24 effectively serve as a hopper to help guide the materials into the storage compartments 56 during the loading.

The unit 10, as just described, is effective in maintaining the heated asphalt stored within the storage compartments 56 in a condition where there is a minimum heat loss therefrom, even under extremely cold ambient conditions. As already noted, part of the inventive contribution hereof is the recognition that it would not be practical to try to minimize heat loss from the heated materials within the storage compartments 56 by the use of heat insulation materials applied directly to the walls which define the compartments 56. Instead, such conventional heat insulation materials, as are used in accordance with the present invention, are applied, instead, to the outer wall construction, namely the sidewalls l6 and 18, the end walls 12 and 14, and the top covering of the unit 10 which consists of the doors 22 and 24. This heat insulation is designated 92 and will be understood to be a conventional material having heat barrier properties or, in other words, an ability to minimize heat transfer. For completeness sake, it should be noted that, of course, in addition to using heat insulation 92 on the outer wall construction, as just noted, that it is also advantageous and desirable to insulate the door 64 to the heating chamber 50, the doors 78, at opposite ends of the unit 10, and also the shoveling doors 72 and 74 which in their closed position form part of the end walls 14 and 12. The location where heat insulation 19 may be omitted is along the bottom of the unit i0, since at this location of the unit, there exists a channel frame '94 (see FIG. 4) which defines a connecting passage @6 between the heating chamber 50 and the previously noted air passageways 48. By and large, the heated air rises quite rapidly from the connecting passageway 96 into the air passageways 48 and, for this reason, it has not been found necessary to insulate the bottom wall 20 which bounds the air passage 96. At this point in the description it is convenient to note that the passages 96 extend beneath the shoveling decks 86 and 88 and are effective in maintaining these decks at an elevated temperature which minimizes the sticking and clogging of asphalt to these surfaces during the shovel removal of the asphalt from the compartments 56.

In summary, a novel aspect, among others of the unit 10 is the use of a continuous, regulated flow or current of heated air through passageways 48 which envelope the asphalt storage compartments 56 in order to provide a heat gradient which minimizes the transfer or loss from the heated stored materials. This continuous flowing of heated air 66 exits from the passageways 48 into the storage compartments 56 and then vents to atmosphere through restricted vent openings 68 and 70. The temperature of the heated air 66 going through the passageways is effectively maintained at or near the temperature of the stored asphalt materials by the functioning, to a large measure, of the heat insulation 92 along the inner surface of the outer wall construction which bounds the passageways 48. That is, the heat insulation 92 which would not be effective in minimizing heat transfer from a stationary body of heated asphalt has been found effective in minimizing heat loss from the continuous current of heated air 66 flowing through the passageways 48.

A latitude of modification, change and substitution is intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features.

lclaim:

1. A heated asphalt storage unit comprising an enclosing outer wall construction bounding a comparatively large first internal volume having at least one venting aperture in an upper portion thereof, a partially enclosing inner wall construction bounding a second internal volume of a lesser extend than said first internal volume of a lesser extent than said first internal volume serving as a heated asphalt storage compartment and having a prescribed operative position within said first internal volume of said outer wall construction, said operative position including the orientation of the upper portion of said inner wall construction in facing relation to said venting aperture and the remainder thereof in a clearance position from said enclosing outer wall construction so as to define an airflow passage therebetween and also the delineation by said inner wall construction of a portion of said first internal volume which is remote from said venting aperture as a heating chamber, heating means operatively disposed within said heating chamber effective to cause the continuous convection flow of heated air between said heating chamber and said venting aperture through said airflow passage, door means closing the top of said heated asphalt storage compartment, atmospheric vent means in said door means to assure a continuous flow of heated air from said heating means to the atmosphere and a consequent heating of all the walls of said compartment, and heat insulation along the side of said outer wall construction bounding said airflow passage effective to minimize heat loss from said continuous convection flow of heated air, whereby an optimum elevated temperature is maintained in said air flowing about said inner wall construction so as to minimize heat loss from heated asphalt within said storage compartment.

2. A heated asphalt storage unit as defined in claim 1 wherein said inner wall construction has a centrally located angularly oriented pair of walls delineating said heating chamber from said asphalt storage compartment, each said angularly oriented wall contributing to gravity movement of said heated asphalt to an exit opening of said storage compartment.

3. A heated asphalt storage unit as defined in claim 1 wherein the total extent of said one or more venting apertures of said outer wall construction is of comparatively small size so as to restrict the movement of said heated air from said asphalt storage compartment, whereby said heated air accumulates within said storage compartment and contributes to maintaining the elevated temperature of said storage asphalt.

4. A heated asphalt storage unit as defined in claim 1 wherein said heating means is an infrared burner and includes means for adjusting the burning rate thereof, whereby the expansion and thus flow rate of heated air produced by said burner is a function of the burning rate thereof.

UNITED STATES PATENT OFFICE CERTlFICATE 0F CORRECTION Patent No. 3 I 76 Dated May 11, 1971 Inventor(s) ANTON H. HELLER It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Claim 1, Line 5, at the end thereof, change "extend" to extent-- Claim 1, Lines 6 and 7 delete "of a lesser extent than said first internal volume" Claim 1, Line 14, change "airflow" to air-flow Claim 1, Line 20 change "airflow" to air-flow Claim 1, Line 26, change "airflow" to air-flow Signed and sealed this 7th day of September 1971.

(SEAL) Attest:

EDWARD M-FLETCHERJR- ROBERT GOTTSCIIALK Attesting 01.1.1061 Acting Commissioner of Patents 

1. A heated asphalt storage unit comprising an enclosing outer wall construction bounding a comparatively large first internal volume having at least one venting aperture in an upper portion thereof, a partially enclosing inner wall construction bounding a second internal volume of a lesser extend than said first internal volume of a lesser extent than said first internal volume serving as a heated asphalt storage compartment and having a prescribed operative position within said first internal volume of said outer wall construction, said operative position including the orientation of the upper portion of said inner wall construction in facing relation to said venting aperture and the remainder thereof in a clearance position from said enclosing outer wall construction so as to define an airflow passage therebetween and also the delineation by said inner wall construction of a portion of said first internal volume which is remote from said venting aperture as a heating chamber, heating means operatively disposed within said heating chamber effective to cause the continuous convection flow of heated air between said heating chamber and said venting aperture through said airflow passage, door means closing the top of said heated asphalt storage compartment, atmospheric vent means in said door means to assure a continuous flow of heated air from said heating means to the atmosphere and a consequent heating of all the walls of said compartment, and heat insulation along the side of said outer wall construction bounding said airflow passage effective to minimize heat loss from said continuous convection flow of heated air, whereby an optimum elevated temperature is maintained in said air flowing about said inner wall construction so as to minimize heat loss from heated asphalt within said storage compartment.
 2. A heated asphalt storage unit as defined in claim 1 wherein said inner wall construction has a centrally located angularly oriented pair of walls delineating said heating chamber from said asphalt storage compartment, each said angularly oriented wall contributing to gravity movement of said heated asphalt to an exit opening of said storage compartment.
 3. A heated asphalt storage unit as defined in claim 1 wherein the total extent of said one or more venting apertures of said outer wall construction is of comparatively small size so as to restrict the movement of said heated air from said asphalt storage compartment, whereby said heated air accumulates within said storage compartment and contributes to maintaining the elevated temperature of said storage asphalt.
 4. A heated asphalt storage unit as defined in claim 1 wherein said heating means is an infrared burner and includes means for adjusting the burning rate thereof, whereby the expansion and thus flow rate of heated air produced by said burner is a function of the burning rate thereof. 